1. Field
The present disclosure relates to a lactate dehydrogenase mutant, a polynucleotide coding for the mutant, a yeast cell including the polynucleotide encoding the mutant, a method of preparing the mutant, and a method of producing lactate by using the same.
2. Description of the Related Art
Lactate is an organic acid that is broadly used in various industrial fields, such as food, pharmaceutics, chemicals, and electronics. Lactate is colorless, odorless, and a low-volatile material that dissolves well in water. Lactate is non-toxic to the human body and thus may be used as a flavor agent, an acidifier, or a preservative. Additionally, in addition to being an environmentally-friendly alternative to a polymer material, lactate is a raw material of a polylactic acid (PLA), which is biodegradable plastic.
PLA is a polyester-based resin that is ring-open polymerized when converted into lactide, which is a dimer, for technical polymerization and may be variously processed into a film, sheet, fiber, plastic, and etc. Thus, the demand for PLA as bioplastic has recently increased to broadly replace conventional typical petrochemical plastic, such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or polystylene (PS).
In addition, lactate includes both a hydroxyl group and a carboxyl group and thus is highly reactive. Accordingly, lactate may easily be converted into an industrially important compound, such as lactate ester, acetaldehyde, or propyleneglycol, and thus has received attention in the chemical industry as an alternative chemical material of the next generation.
Currently, lactate is commercially produced through a petrochemical synthesis process and a biotechnical fermentation process. The petrochemical synthesis process includes oxidation of ethylene derived from crude oil, a hydrocyanation addition reaction via acetaldehyde to prepare lactonitrile, distillation to refine the same, and a hydrolysis reaction using hydrochloric acid or sulfuric acid. Additionally The biotechnical fermentation process may produce lactate by using a renewable carbohydrate material, such as starch, sucrose, maltose, glucose, fructose, and xylose, as a substrate.
Despite the availability of these processes, there remains a need for a method of efficiently preparing a lactate dehydrogenase mutant and a method of producing lactate by using the same are required.